Inertial sensors comprise a diverse classification of sensors used to measure angular velocity and linear acceleration, with varying levels of accuracy and range. Particularly in the automotive field, inertial sensor applications have recently become more widespread and are applied in a variety of applications to improve the safety, performance, and comfort of automotive vehicles. Present applications of inertial sensors in automobiles range from advanced Anti-lock Braking Systems (ABS) that measure the longitudinal velocity and acceleration of a vehicle to determine if the chassis is still moving, to more complex systems such as driver assistance systems and even autonomous vehicle operation. In pursuit of more advanced systems, automotive manufacturers continue to push the boundaries of the capability of inertial sensors. This pursuit has created a need for innovative, cost effective solutions to improve the capability of inertial sensors.
Inertial sensors range in accuracy and performance capability, but generally suffer from some common deficiencies. Common sources of error in inertial sensor accuracy include: temperature variations, flicker noise, thermo-mechanical white noise, and bias (offset) instability. The bias of an inertial sensor output signal or rate signal refers to the initial error of the inertial sensor output compared to the true measurement values being experienced by the inertial sensor. Bias is one of the primary sources of error because if left uncorrected, it results in a steadily growing angular or linear positional error. Temperature variations due to changes in environmental conditions also cause fluctuations in the output of inertial sensors and increase the error in inertial sensor measurements. The deficiencies of inertial sensors are also emphasized when inertial sensors are applied in increasingly complex equations to model vehicle behavior. The most prominent examples of this emphasis are increased errors due to various inertial sensor measurements which may be propagated through the integral relationships among rate measurements, velocity, and position.
The combined issues related to the applications of inertial sensors demonstrate some of the limiting factors inhibiting cost-effective applications of inertial sensors. Ensuring accuracy of these sensors is imperative to promoting advanced vehicle systems that may be widely applicable in automotive vehicles. The methods and systems disclosed herein may provide for improved inertial sensor accuracy and cost-effective implementation to promote improved safety and diagnostics in automotive vehicles.